A COMPARISON OF TWO DOSING REGIMENS OF INTRA-VAGINALLY ADMINISTERED MISOPROSTOL FOR PRE-INDUCTION CERVICAL RIPENING AND INDUCTION OF LABOUR

Abstract

To compare the effectiveness of two dosing regimens (25μg and 50 μg) of misoprostol for cervical ripening/induction of labour, to compare the adverse effects on labour and fetal outcome of the two groups.
METHODOLOGY

The study was a prospective, randomized study of healthy pregnant women, with singleton fetus who registered for antenatal care and delivery at the University College Hospital (UCH) Ibadan, between 1st September 2005 and 31st May 2006 and who met the study criteria. One hundred and twenty (120) patients were recruited to participate and one hundred and eighteen (118) agreed. No patient withdrew from the study. The patients were assigned by means of table of random numbers to receive either 25 microgram or 50 microgram of misoprostol (cytotec ® tablet, Searle & Co. Chicago). Sixty-three (63) patients received 25μg and fifty-five (55) received 50μg.
RESULTS

Significantly higher number of patients achieved spontaneous labour in the 50 μg group than in 25 μg group (96.4% vs. 84% (P<0.05). The mean interval between the first dose and delivery was shorter in the 50 μg group though this did not assume statistical significance (P = 0.152).

There was no significant different between the two groups in the number of doses needed to achieve favorable cervical score of ≥ 6 or spontaneous labour (1.8 ±1.1 vs. 1.7 ± 0.7, P = 0.689) among the patients that achieved vaginal delivery. More patients (97.9%) in the 50 μg group who achieved vaginal delivery did so within 24 hours compared to (89.6%) in the 25 μg group. However no patients in the either arm of the study received the maximum dose(200μg) of the study drug.

The need for oxytocin augmentation of labour among those that developed spontaneous labour was higher among the 25 μg group than in the 50μg group (39.7% vs. 16.4%, P=0.007).

The incidence of caesarean section was similar in the two groups 8.0% vs. 11% for 25 μg and 50 μg respectively; with similar proportions also achieving vaginal delivery, 92% vs. 89% for 25 μg and 50 μg respectively. Overall the route of delivery did not differ significantly between the groups.

The number of neonates with 1-minute and 5 minutes Apgar score less than 7 did not differ significantly between the groups, also the number of neonates admitted into special baby care unit and the indications for admission were not statistically different. However meconium stained liquor was recorded in significantly higher number of patients in 50 μg group than in the 25 μg group (9.1% vs. 0.0%), but none of the neonate had features suggestive of meconium aspiration.

Labour complications, which included precipitate labour, tachysctole (>5 contractions in 10 minutes for two consecutive 10 minutes period), fetal distress

(fetal bradycardia or tachycardia) were more in the 50 μg groups. Two patients in 25 μg group experienced vomiting.
CONCLUSION

The two dose regimens 25μg and 50μg were both effective in cervical ripening / induction of labour. 50μg resulted in relatively faster delivery and less need for augmentation of labour; however it was associated with more labourcomplications compared to 25μg.

A COMPARISON OF TWO DOSING REGIMENS OF INTRA-VAGINALLY ADMINISTERED MISOPROSTOL FOR PRE-INDUCTION CERVICAL RIPENING AND INDUCTION OF LABOUR